Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
2002-04-03
2003-11-18
Moulis, Thomas N. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C123S506000
Reexamination Certificate
active
06647963
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic valve for a high pressure fuel supply apparatus which, when supplying high pressure fuel from a fuel pump, is capable of controlling the flow rate of the high pressure fuel.
FIG. 6
is a block diagram of a fuel supply system in a vehicle internal combustion engine including a conventional electromagnetic valve for a high pressure fuel supply apparatus. In
FIG. 6
, fuel
2
stored in a fuel tank
1
is discharged from the fuel tank
1
by a low pressure pump
3
and passes through a filter
4
; and, after the pressure of the fuel
2
is adjusted by a low pressure regulator
5
, the fuel
2
is supplied to a high pressure fuel supply apparatus
6
which is a high pressure pump. While only the flow rate of the fuel
2
that is necessary for fuel injection is adjusted into high pressure fuel by the high pressure fuel supply apparatus
6
, the fuel
2
is supplied into a delivery pipe
9
disposed in an internal combustion engine (not shown). The extra amount of the fuel
2
is relieved into between a low pressure damper
12
and a suction valve
13
by an electromagnetic valve
17
.
Also, the necessary fuel rate is decided by a control unit (not shown) and the electromagnetic
17
is also controlled by the control unit. The thus supplied high pressure fuel is jetted out in the form of high pressure mist from fuel injection valves
10
connected to the delivery pipe
9
into the cylinders of the internal combustion engine. In case where the pressure of the interior of the delivery pipe
9
turns into an abnormal pressure (the pressure for opening a high pressure relief valve), a filter
7
and a high pressure relief valve
8
are respectively opened to thereby prevent the delivery pipe
9
against damage.
The high pressure fuel supply apparatus
6
, which is a high pressure pump, includes a filter
11
for filtering the fuel supplied, a low pressure damper
12
for absorbing the pulsations of the low pressure fuel, and a high pressure fuel pump
16
which pressurizes the fuel supplied through the suction valve
13
to thereby jet out the high pressure fuel through a jet-out valve
14
.
Now,
FIG. 7
is a section view of a conventional high pressure fuel supply apparatus. In
FIG. 7
, the high pressure fuel supply apparatus
6
includes a casing
61
, a high pressure fuel pump
16
consisting of a plunger pump disposed within the casing
61
, an electromagnetic valve
17
and a low pressure damper
12
, while these components are formed as an integrated unit.
In the high pressure pump
16
, there are formed a sleeve
160
, and a fuel pressurizing chamber
163
enclosed by a plunger
161
which is inserted into the high pressure pump
16
in such a manner that it is able to slide within the sleeve
160
. The other end of the plunger
161
is contacted with a tappet
164
; and, the tappet
164
is contacted with a cam
100
in order to be able to drive the high pressure fuel pump
16
. The cam
100
is formed integrally or coaxially with the cam shaft
101
of the engine and can be operated in linking with the rotation of the crankshaft to move the plunger
161
reciprocatingly along the profile of the cam
100
. The capacity of the fuel pressurizing chamber
163
varies according to the reciprocating motion of the plunger
161
and thus the fuel, which is pressurized into high pressure fuel, can be jetted out from the jet-out valve
14
.
The high pressure fuel pump
16
is structured in the following manner: that is, a first plate
162
, the suction valve
13
, a second plate
166
and the flange portion of the sleeve
160
are held by and between the casing
61
and the end face of a spring guide
165
as well as are fastened by a bolt
180
. The first plate
162
includes a fuel suction port
162
a
for sucking the fuel from the low pressure damper
12
into the fuel pressurizing chamber
163
, and a fuel jet-out port
162
b
for jetting out the fuel from the fuel pressurizing chamber
163
.
The suction valve
13
, which has a thin-plate shape, is held by and between the first and second plates
162
and
166
, while a valve body of the suction valve
13
is disposed in the fuel suction port
162
a
. The jet-out valve
14
is disposed on the top portion of the fuel jet-out port
162
b
and is allowed to communicate with the delivery pipe
9
through a high pressure fuel jet-out passage
62
formed within the casing
61
. Also, for suction of the fuel, there is interposed a spring
167
for pressing down the plunger
161
in a direction to expand the fuel pressurizing chamber
163
in such a manner that the spring
167
is compressed between the spring guide
165
and a spring holder
168
.
Now,
FIG. 8A
is a section view of the conventional electromagnetic valve for a high pressure fuel supply apparatus; and,
FIG. 8B
shows section views respectively taken along the lines A—A, B—B and C—C shown in FIG.
8
A. Also,
FIG. 9
shows enlarged section views of the contact portion between a valve member and a valve seat. In
FIGS. 8A and 8B
, the electromagnetic valve
17
includes an electromagnetic valve main body
170
incorporated into the casing
61
of the high pressure fuel supply apparatus
6
and including a fuel passage
172
therein, a valve seat
173
disposed within the fuel passage
172
of the electromagnetic valve main body
170
, a hollow cylindrical-shaped valve member
174
detachable from and contactable with the valve seat
173
within the electromagnetic valve main body
170
to thereby open and close the fuel passage
172
, and a compression spring
175
for pressing the valve member
174
against the valve seat
173
. The terminal
176
of a solenoid coil
171
is guided to a connector
178
and is connected to an external circuit (not shown).
In the jet-out stroke of the high pressure fuel pump
16
, at the time when the flow rate required by the control unit (not shown) is jetted out, the solenoid coil
171
wound around the periphery of a core
177
fixedly secured to the electromagnetic valve main body
170
of the electromagnetic valve
17
is excited and, due to the thus-excited electromagnetic force, the valve member
174
is detached from the valve seat
173
against the operation force of the compression spring
175
and is thereby opened.
The fuel, as shown by arrow marks in
FIG. 9
, moves from the fuel passage
172
, passes through a clearance between the valve seat
173
and valve member
174
, and flows into an oil passage
174
a
which is a hollow portion of the valve member
174
. The fuel, which has flown into the oil passage
174
a
, moves through cut-out oil passages
174
b
respectively formed in the outer peripheral portion of the valve member
174
as well as through a diameter-direction oil passage
181
a
formed in a stopper
181
, and is then relieved to the low pressure side.
As described above, by relieving the fuel
2
within the fuel pressurizing chamber
163
to the low pressure side between the low pressure damper
12
and suction valve
13
, the pressure of the interior of the fuel pressurizing chamber
163
is reduced down to the pressure of the delivery pipe
9
or lower, thereby closing the jet-out valve
14
. After then, the valve member
174
of the electromagnetic valve
17
remains open until the high pressure fuel pump
16
moves to the suction stroke. By controlling the valve opening timing of the electromagnetic valve
17
, the quantity of the fuel to be jetted-out to the delivery pipe
9
can be adjusted.
However, in the conventional high pressure fuel supply apparatus, as shown in
FIG. 9
, since the valve seat
173
and valve member
174
are contacted with each other in a flat shape, when the valve member
174
is opened, the flow of the fuel in the periphery of the valve member
174
turns from sudden reduction to sudden expansion, the fuel flow detaches from the wall surface of the valve member
174
on the downstream side to thereby cause a backward flow (eddy) and thus narrow the oil passage, which results in the large fuel pressure
Onishi Yoshihiko
Tochiyama Shigenobu
Mitsubishi Denki & Kabushiki Kaisha
Moulis Thomas N.
LandOfFree
Electromagnetic valve for high pressure fuel supply apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electromagnetic valve for high pressure fuel supply apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electromagnetic valve for high pressure fuel supply apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3183546